Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

[Federal Register Volume 86, Number 231 (Monday, December 6, 2021)]
[Rules and Regulations]
[Pages 68905-68907]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-26365]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0546; Project Identifier MCAI-2021-00387-P; 
Amendment 39-21815; AD 2021-23-17]
RIN 2120-AA64


Airworthiness Directives; Hoffmann GmbH & Co. KG Propellers

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2020-25-05 
for all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 
2020-25-05 required amending the existing aircraft flight manual (AFM) 
with abnormal propeller vibration instructions. AD 2020-25-05 also 
required visual inspection and non-destructive test (NDT) inspection of 
the propeller hub and, depending on the results of the inspections, 
replacement of the propeller hub with a part eligible for installation. 
AD 2020-25-05 also required replacement of the propeller hub before 
exceeding 30 years since the date of manufacture. This AD was prompted 
by reports of cracks at different positions on two affected propeller 
hubs and subsequent manufacturer revision of the service information, 
which showed that the 30-year life limit of the propeller hub is no 
longer needed. This AD requires amending the existing AFM by inserting 
abnormal propeller vibration instructions, visual inspection and NDT 
inspection of the propeller hub and, depending on the results of the 
inspections, replacement of the propeller hub with a part eligible for 
installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective January 10, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of January 10, 
2022.

ADDRESSES: For service information identified in this final rule, 
contact Hoffmann GmbH & Co. KG, K[uuml]pferlingstrasse 9, 83022, 
Rosenheim, Germany; phone: +49 0 8031 1878 0; email: prop.com">info@hoffmann-prop.com; website: prop.com">https://hoffmann-prop.com. You may view this service 
information at the FAA, Airworthiness Products Section, Operational 
Safety Branch, 1200 District Avenue, Burlington, MA 01803. For 
information on the availability of this material at the FAA, call (781) 
238-7759. It is also available at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0546.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0546; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this AD, the mandatory 
continuing airworthiness information (MCAI), any comments received, and 
other information. The address for Docket Operations is Document 
Operations, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Michael Schwetz, Aviation Safety 
Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA 
01803; phone: (781) 238-7761; fax: (781) 238-7199; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2020-25-05, Amendment 39-21347 (85 FR 
78702, December 7, 2020), (AD 2020-25-05). AD 2020-25-05 applied to all 
Hoffmann model HO-V 72 propellers. The NPRM published in the Federal 
Register on July 6, 2021 (86 FR 35416). The NPRM was prompted by 
reports of cracks at different positions on two affected propeller hubs 
and subsequent manufacturer revision of the service information, which 
showed that the 30-year life limit of the propeller hub is no longer 
needed. In the NPRM, the FAA proposed to continue to require amending 
the existing AFM with abnormal propeller vibration instructions. In the 
NPRM, the FAA also proposed to continue to require visual inspection 
and NDT inspection of the propeller hub and, depending on the results 
of the inspections, replacement of the propeller hub with a part 
eligible for installation. The FAA is issuing this AD to address the 
unsafe condition on these products.
    The European Union Aviation Safety Agency (EASA), which is the 
Technical Agent for the Member States of the European Community, has 
issued EASA AD 2020-0226R1, dated March 31, 2021

[[Page 68906]]

(referred to after this as ``the MCAI''), to address the unsafe 
condition on these products. The MCAI states:

    Cracks have been reported at different positions on two affected 
parts, both installed on Slingsby T67 ``Firefly'' aeroplanes. One 
crack was found during scheduled inspection, the other crack during 
an unscheduled inspection after abnormal vibrations occurred. Both 
cases are under investigation by Hoffmann Propeller.
    This condition, if not detected and corrected, could lead to in-
flight propeller detachment, possibly resulting in damage to the 
airplane and/or injury to persons on the ground.
    To address this potential unsafe condition, Hoffmann issued the 
SB, providing applicable instructions.
    For the reasons described above, EASA issued Emergency AD 2020-
0226-E to require inspections of affected parts and, depending on 
findings, replacement, and introduces a life limit for affected 
parts. That [EASA] AD also required, for certain aeroplanes, 
amendment of the applicable Aircraft Flight Manual (AFM).
    Since that [EASA] AD was issued, recent analyses of inspection 
results showed that the life limit of 30 years is no longer 
necessary and Hoffmann Propeller issued Revision D of the SB 
accordingly.
    This [EASA] AD is revised to delete the life limit and to 
introduce a clarification for corrective action(s) during overhaul 
in paragraph (6) [of EASA AD].

    You may obtain further information by examining the MCAI in the AD 
docket at https://www.regulations.gov by searching for and locating 
Docket No. FAA-2021-0546.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from one individual commenter. The 
individual commenter supported the NPRM without change.

Clarification of Required Actions

    The FAA revised paragraph (g), Required Actions, of this AD by 
clarifying that the propeller hub must be replaced with a part eligible 
for installation if any crack is detected during an overhaul 
inspection.

Conclusion

    The FAA reviewed the relevant data, considered the comment 
received, and determined that air safety requires adopting the AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. This AD is adopted as proposed in the 
NPRM.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Hoffmann Propeller GmbH & Co. KG Service Bulletin 
SB E53, Rev. D, dated February 18, 2021. The service bulletin describes 
procedures for visual and NDT inspections of the propeller hub for 
cracks. This service information is reasonably available because the 
interested parties have access to it through their normal course of 
business or by the means identified in ADDRESSES.

Costs of Compliance

    The FAA estimates that this AD affects 35 propellers installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Amend AFM.............................  1 work-hour x $85 per                 $0             $85          $2,975
                                         hour = $85.
Visually inspect propeller hub........  1 work-hour x $85 per                  0              85           2,975
                                         hour = $85.
NDT inspect propeller hub.............  8 work-hours x $85 per                 0             680          23,800
                                         hour = $680.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
mandated inspections. The FAA has no way of determining the number of 
aircraft that might need this replacement:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace propeller hub.........................  5 work-hours x $85 per hour =             $1,600          $2,025
                                                 $425.
----------------------------------------------------------------------------------------------------------------

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    The FAA is issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, General requirements. 
Under that section, Congress charges the FAA with promoting safe flight 
of civil aircraft in air commerce by prescribing regulations for 
practices, methods, and procedures the Administrator finds necessary 
for safety in air commerce. This regulation is within the scope of that 
authority because it addresses an unsafe condition that is likely to 
exist or develop on products identified in this rulemaking action.

Regulatory Findings

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities under the criteria 
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

[[Page 68907]]

The Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive 2020-25-05, Amendment 39-21347 (85 
FR 78702, December 7, 2020); and
0
b. Adding the following new airworthiness directive:

2021-23-17 Hoffmann GmbH & Co. KG: Amendment 39-21815; Docket No. 
FAA-2021-0546; Project Identifier MCAI-2021-00387-P.

(a) Effective Date

    This airworthiness directive (AD) is effective January 10, 2022.

(b) Affected ADs

    This AD replaces AD 2020-25-05, Amendment 39-21347 (85 FR 78702, 
December 7, 2020).

(c) Applicability

    This AD applies to all Hoffmann GmbH & Co. KG model HO-V 72 
propellers.

(d) Subject

    Joint Aircraft System Component (JASC) Code 6114, Propeller Hub 
Section.

(e) Unsafe Condition

    This AD was prompted by reports of cracks at different positions 
on two affected propeller hubs. The FAA is issuing this AD to 
prevent failure of the propeller hub. The unsafe condition, if not 
addressed, could result in release of the propeller, damage to the 
airplane, and injury to persons on the ground.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) Before the next flight after December 22, 2020 (the 
effective date of AD 2020-25-05), amend the existing aircraft flight 
manual by inserting the procedure: ``Abnormal propeller vibrations: 
As applicable, reduce engine RPM.''
    (2) Before the next flight after the effective date of this AD, 
and thereafter, before the next flight after any flight where 
abnormal propeller vibrations have been experienced, visually 
inspect propeller hub HO-V 72 ( ) ( )-( )-( ) for cracks using 
paragraph 2.1 of Hoffmann Propeller GmbH & Co. KG Service Bulletin 
SB E53, Rev. D, dated February 18, 2021 (the SB).
    (3) Within 20 flight hours after the effective date of this AD, 
perform a non-destructive test (NDT) inspection of propeller hub HO-
V 72 ( ) ( )-( )-( ) using paragraph 2.3 of the SB.
    (4) During each overhaul of propeller hub HO-V 72 ( ) ( )-( )-( 
) after the effective date of this AD, perform an NDT inspection 
using paragraph 2.3 of the SB.
    (5) If, during any inspection required by paragraph (g)(2), (3), 
or (4) of this AD, any crack is detected, replace propeller hub HO-V 
72 ( ) ( )-( )-( ) with a part eligible for installation.

(h) Definition

    For the purpose of this AD, a ``part eligible for installation'' 
is a propeller hub HO-V 72 ( ) ( )-( )-( ) with zero hours time 
since new or a propeller hub HO-V 72 ( ) ( )-( )-( ) that has passed 
an NDT inspection using paragraph 2.3 of the SB.

(i) Non-Required Actions

    (1) Sending the propeller to Hoffmann for investigation, as 
contained in paragraph 2.1 of the SB, is not required by this AD.
    (2) Reporting propeller hubs with cracks to Hoffmann, as 
contained in paragraph 2.3 of the SB, is not required by this AD.

(j) Credit for Previous Actions

    You may take credit for the initial visual inspection and NDT 
inspection of the propeller hub required by paragraphs (g)(2), (3), 
and (4) of this AD if you performed any of these actions before the 
effective date of this AD using Hoffmann Propeller GmbH & Co. KG SB 
E53, Rev. A, dated October 9, 2020; Rev. B, dated October 14, 2020; 
or Rev. C, dated December 9, 2020.

(k) Special Flight Permit

    A special flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to operate the airplane to a service facility to 
perform the NDT inspection. Special flight permits are prohibited to 
perform the visual inspection of the propeller hub.

(l) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston ACO Branch, FAA, has the authority to 
approve AMOCs for this AD, if requested using the procedures found 
in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request 
to your principal inspector or local Flight Standards District 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in paragraph (m)(1) of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(m) Related Information

    (1) For more information about this AD, contact Michael Schwetz, 
Aviation Safety Engineer, Boston ACO Branch, FAA, 1200 District 
Avenue, Burlington, MA 01803; phone: (781) 238-7761; fax: (781) 238-
7199; email: [email protected].
    (2) Refer to European Union Aviation Safety Agency (EASA) AD 
2020-0226R1, dated March 31, 2021, for more information. You may 
examine the EASA AD in the AD docket at https://www.regulations.gov 
by searching for and locating Docket No. FAA-2021-0546.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Hoffmann Propeller GmbH & Co. KG (Hoffmann) Service Bulletin 
SB E53, Rev. D, dated February 18, 2021.
    (ii) [Reserved]
    (3) For Hoffmann service information identified in this AD, 
contact Hoffmann GmbH & Co. KG, K[uuml]pferlingstrasse 9, 83022, 
Rosenheim, Germany; phone: +49 0 8031 1878 0; email: prop.com">info@hoffmann-prop.com; website: prop.com">https://hoffmann-prop.com.
    (4) You may view this service information at FAA, Airworthiness 
Products Section, Operational Safety Branch, 1200 District Avenue, 
Burlington, MA 01803. For information on the availability of this 
material at the FAA, call (781) 238-7759.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on November 4, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-26365 Filed 12-3-21; 8:45 am]
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